This invention relates to a positioning device in which a body is displaceable and rotatable in a plane by means of three drives.
Various positioning devices are known in which a body is displaceable and rotatable in a plane by means of three drives. These known devices have the drawback that at least one of the drives is displaced together with the body, whereby these devices are relatively heavy and sluggish.
The invention has as its object to propose a positioning device which is simply constructed and in which the masses in motion are as small as possible.
This object is achieved according to the invention in that three elongated, non-parallel guide elements are rigidly connected to the body, each guide element is received in a longitudinally displaceable way in a translational bearing, each translational bearing is pivotable about a pivot axis directed perpendicular to the plane, each pivot axis is disposed on a rotor spaced apart from its rotational axis and parallel to this rotational axis, and the three rotors are disposed axis-parallel and are rotatable by means of the drives.
This construction has the advantage that it is built simply and that in particular none of the drives has to be moved along by another drive.
According to a preferred embodiment of the invention, the three rotors are disposed coaxially, whereby the positioning device can be particularly simply constructed.
If, according to a further special embodiment of the invention, the spacing of the rotor axis to the pivot axis is the same for all three rotors, all three pivot axes move on the same circular path, whereby the control of the positioning device can be designed much more simply.
The guide elements are preferably designed straight and are disposed on the body with a mutual angular spacing of 120 degrees. These measures, too, simplify control of the positioning device.
If, according to a further preferred embodiment of the invention, the drives are motors, each motor being connected to one of the rotors via a gearing, motors commonly available on the market can be used to achieve the positioning device.
According to an especially preferred embodiment of the invention, the drives are electro-motors, which have a common stator, and there are elements on each of the rotors that cooperate electromagnetically with corresponding elements disposed on the stator. Parts can be saved in this way, resulting in an especially light and fast-reacting positioning device.